A power amplifier is generally used to provide the final stage of amplification where the delivery of radio frequency (RF) power is required. Most power amplifiers, when pushed to deliver their maximum output power, produce at their outputs one or more harmonic and/or inter-modulation spectral components of the input signal of the amplifiers. While the input signal may be contained well within a permissible spectral band, some of the harmonic and inter-modulation components may fall outside the permissible band.
Furthermore, non-linear amplifiers cause spectral re-growth. Methods to control spectral re-growth, such as using pre-distorter circuits or highly linear but less-efficient amplifiers have not sufficiently mitigated the problem. Accordingly, it is desirable to provide for the mitigation of spectral re-growth and of other effects caused by non-linear amplification.